4.3.5.2.6.2. Number of colonies/replicates – statistical power

6 to 10 colonies per treatment group (exposure/control)
should overcome the inter-colony variability (EFSA, 2012). The number of
replicates per trial depends on the magnitude of effects that the test should
detect. The statistical power of the test should always be calculated (see Pirk
et al., 2013).